Unlike the other funerary monuments, the Tomb of Raimondo di Sangro appears sober, almost severe. Designed by Russo in 1759, when the seventh Prince of Sansevero was still alive, it comprises two essential elements: a complex of sculptured emblems set in a great arch, in seventeenth-century style, and a plaque with a long eulogy to di Sangro. Between these is the marble frame with the Portrait of the Prince.
The symbols Raimondo di Sangro wanted for his tomb commemorate his earthly glory earned through his military success and scientific-literary output. A Breastplate and a helmet are surrounded by insignia, flags, pikes, halberds and other weapons. There are also books, parchments, set squares and a globe. From the far right of the arch hangs the sash of the Knights of the Order of San Gennaro, a decoration he received in 1740.
The most interesting and original part of the monument is the great marble slab with its inscription. The funeral eulogy, in fact, is not engraved, but in relief, and shows no trace of chisel marks. This was achieved thanks to a procedure based on chemical solvents devised by the Prince himself. The letters “in relief like a cameo” – as an eighteenth-century source puts it – are white, and originally contrasted with the pink base of the slab, but today the colour has largely been lost. A very delicate design of vine-leaves and bunches of grapes, also in relief, decorates the perimeter of the plaque. The finesse of the decorations shows that they could not have been done with a chisel, since it would not have been possible to “cut the marble so thin”. Almost all the travellers and the guides from the eighteenth century onwards describe this aspect of the Tomb.
Equally important is the content of the dedication to Raimondo, nominally composed by the Priest of the Sansevero Chapel, but without doubt dictated by the Prince himself. It mentions the descent of the household from Emperor Charlemagne, listing the heraldic titles, the decorations and positions held by Raimondo, and praises his publication on the subject of infantry (also lauded by Federico II of Prussia). Especially, however, it praises his role as author of the iconographic design of the Sansevero Chapel, as well as his exceptional gifts in experimentation, describing him as an “extraordinary man, gifted in all he dared to undertake […] famous investigator into the most recondite mysteries of Nature”.